But Carrazzo also insists they have always gained permission from the club doctor before using the substances.

The unfolding crisis at Essendon has put the spotlight on what players take to help with their physical training and recovery.

"I've never personally been someone who's taken many supplements at all - protein is probably as far as I would go," Carazzo said.

"Everything at our club gets ticked off by the doctor.

"I know some guys (have bought) stuff over the internet in the past and they're always careful to check with our doctor Ben Barresi first and he'll check the list with what's allowed and what's not allowed.

"In this day and age, you've just got to be super, super careful."

Carrazzo was also confident that given the processes in place at Carlton, something like the Essendon crisis could never happen at his club.

Collingwood captain Nick Maxwell also said on Wednesday that players would now be more likely to question supplements they are given.

"These guys are experts in their field, and I know that all they want is the best for me as a player, but also for me to perform at the football club," Maxwell told SEN radio.

"There's probably going to be a lot more players asking questions when they are given these things."

Meanwhile, St Kilda forward Stephen Milne said he was already concerned about injections.